The Inheritance of Virescent Yellow and Red Plant Colors in Cotton.

Deficiencies in the amount of chlorophyll in the cotton plant have been reported in relatively few instances. BALLS (1908) made a cross between an upland cotton with light green leaves and a dark green Egyptian cotton. He states that in the Fz generation, plants with light green leaves and plants with dark green leaves appeared in a 3 : 1 ratio. STROMAN and MAHONEY (1925) recovered two chlorophyll deficient types in the Fz generation from crosses between upland and Egyptian cottons (Gossypium hirsutumXG. barbademe). The first type, yellow seedlings, was due to 2 recessive genes, the segregating plants producing 15 green: 1 yellow seedling. The second type was a pattern seedling character in which certain irregular areas devoid of chlorophyll on the cotyledon leaves were surrounded by normal green pigment. These pattern characters were inherited as recessives. In some cases two, in others three, pairs of genes were concerned. HARLAND (1932) also recovered from several different interspecific crosses various types which were partially deficient in chlorophyll. HORLACHER and KILLOUGH (1931) induced in upland cotton (G. hirsutunz) by radiations a type that produces yellow seedlings lacking in chlorophyll. This yellow is lethal and a simple recessive to green, heterozygous plants producing 3 green: 1 yellow seedling. The yellow seedlings die after using up the stored food material of the seed. In all such chlorophyll deficient types which have been observed by the authors, the deficient portions are yellow due to the presence of carotinoid2 pigments and the absence of green chlorophyll. No portion of a cotton plant devoid of carotinoid pigments was observed. The yellow seedling character mentioned above is not to be confused with the virescent yellow mature plant color discussed in this paper.